Crystal detector



F. E. MANN CRYSTAL DETECTOR April 17, 1928. 1,666,462

Filed Nov. 19. 1923 Patented Apr. 17, 1928.

UNITED STATES PATENT OFFICE.

FREDERICK E. ,MANN,- OF CHERRYDALE, VIRGINIA.

' CRYSTAL Application filed November This invention relates to crystal detectors particularly useful in connection with radio apparatus, and has particular reference to crystal detectors of that type embodying a contact spring mounted to be moved into engagement with and over the surface of the fine or Vernier adjustment of the crystal toward or away from the contact spring whereby the pressure with which said contact spring engages the'crystal may be finely adjusted for effecting a very sensitive tuning offlthe radio apparatus with which the tie tector is employed.

Another object of the invention is 'to embody the above mentioned fine or Vernier adjustment in a crystal'detector 'in' such man- 7 nor that the detector will be simple and durable in construction as well as extremely efli-' cient in operation so as to meet with all of the requirements for a successful commer cial use. 7 7 r 1 Another object of the invention is to provide a fine or Vernier adjustment of the above character by meansof a structure including a resilient spring 'upon which the crystal is mounted, and by which the same is normally'urged toward the contact spring, and an adjusting screw associated with the spring for causing the latter to fiex' away from the contact spring or to allow the same to yield toward the contact spring as desired.

Still another object of the invention is to provide simple and eflicient means for mounting the crystal carrying spring so that this mounting may serve for also mounting the supporting post of the crystal contacting spring. j

Other objects will appear as the nature of the invention is better understood, and the same consists in the novel form, combination, and arrangement of parts hereinafter more fully described, shown in the accompanying drawing and claimed.

In the drawing, wherein like reference characters indicate corresponding parts throughout the several views: a

Figure 1 is aftop'plan view of one form of crystal detector constructed in accordance with the present invention.

Figure 2 is a side'elevational View thereof partly broken away and in section, and

DETECTOR.

19, 1923. Serial No. 675,676.

Figure 3 is a vertical transverse sectional view, taken substantially upon the line 3-3 of Figure 2.

In the form of the invention shown, the devicejembodies a base plate 5 of suitable insulating material at the corners of one end of which are provided suitable threaded binding posts 6 upon which are snapped resilient cli s 7 for quick detachable reception of the jam s upon the wires of the receiving circuit of a radio set.

A screw 8 extends upwardly through the base plate 5 between the clips 7, and this screw also extends centrally and upwardly through a hollow boss 9 provided upon the u per surface of the base plate 5,"and upon w ich rests one end of an, elongated spring Y strip 10 that is preferably constructed of by any suitable means such as a screw 14,

and disposed upon the end of "the strip 10 that rests upon the boss 9 is a washer '15 of insulating material through which the screw 8 also passes. A post 16 is provided upon the washer 15 and has a longitudinal socket in its lower end into which the screw 8 is threaded, whereby said post is rigidly .attached-upon the washer 15 and whereby the post, washer, spring strip 10 and boss 9 are firmly clamped in contiguous relation '7 with the plate 5.

The upper end of the post' 16 is longi-c tudinally slotted to provide a pair of arms, between which is pivoted the lower end of an upwardly extending arm 17 by means of a.

post 16 rigidly fastened tothe base screw 18 or the'like, whereby said arm 17 is free to swing in a vertical plane toward and away from the crystal carrying cup 12.

The upper end of the arm 17 is formed with Y a ball or ball shaped head 19 against opposite sides of which are clamped adjacent ends ofspaced parallel plates 20, which adjacent ends of the-plates 20 are provided with segmental spherical sockets in which the ball head 19 is'seated. The other free ends of the plates are provided with scgmental spherical opposed sockets or recesses upon their inner surfaces in which is seated the opposite sides of a ball element 21 provided rigidly upon the central portion of the stem 22 that has a finger piece or knob 23 rigid with the upper end thereof and to the lower end of which is provided the usual contact spring 2%. The manner in which the plates 20 are clamped against opposite sides of the ball members 19 and 21 allow for a substantially universal movement of said plates relative to the arm 17 and a similar movement of the stem 22 relative to the plate 20, the clamping of the plate 20 against the ball members 19 and 21 being preferably effected by means of a screw 25 extending transversely through the central p 26, the'threads of which are of extremely fine portion of the plate 20 and having threaded engagement with one of the latter furthest from the head of the screw 25..

The plate 5 is provided with a substantially central opening adjacent that end of the same opposite to the end to which the post 16 is connected, and within this opening is secured an internally threaded sleeve pitch. The preferred manner of securing the sleeve 26 in place consists in providing the upper end of the same wlth an integral flange 27, adapted to engage the upper surface of the base plate 5 about the opening in which the sleeve is fitted, said flange 27 being clamped into engagement with the upper surface of the base plate 5, by means of a nut 28 threaded upon the lower end of the sleeve 26 within arecess provided in the under surface of the base plate 5.

An adjusting screw 29 is threaded into the sleeve 26 and passes through the free end of the spring strip 10. This screw 29 is provided upon its upper end with a suitable knob 30 that rests upon the upper surface of the spring strip 10 so that when the screw 29 is threaded into the sleeve 26, the spring strip 10 is caused to flex downwardly or away from the spring contact 24 supported by thepost 16. The under surface of the base plate 5 may be provided with a groove 31 in which a wire may be positioned to electrically connect the sleeve 26 with one of the binding posts ,6, while another groove" 32 may be provided in the under surface of the base plate. 5, in whicha wire may be positioned for connecting the screw 8 and post 16 electrically with the other binding post 6. In assembling the device, the screws 18 and 25 are adjusted sufficiently tight to obtain sufiicient friction against the arm 17 and the ball members 19 and 21 so as to insure sufficient friction for maintaining the arm 17 in any desired angular adjustment I stem 22 in any adjusted position to which it is fed relative to the plate 20.

In operation, assuming that the screw 29 is partly, at least, threaded into the sleeve 26, the operator will simply grasp the knob 23 so as tomanipulate the stem 22, plate 20 and arm 17, for bringing the depending end of the spring contact 24 into engagement with the desired point on the surface of the crystal 13. When this is done, a rough adjustment of the spring contact 2& with relation to the crystal is had. The knob 30 is then turned, for threading the screw 29 into or out of the sleeve 26, so as to effect a very gradual or fine adjustment of the crystal toward or away from the contact spring 24, whereby the pressure with whichsaid spring 2t engages the crystal may be regulated to'a' fine degree, whereby afvery sensitive tuning of the radio receiving set with which the detector is used, may

be had. It is of'course', understood that,

when the screw 29 is threaded outwardly of the sleeve 26 in an upward direction, the spring strip 10 will automatically flex upwardly with its free end maintaining engagement with the lower end of thecknob 30 so as to automatically move the crystal toward the contact spring 245, but when the screw 29 is threaded downwardly into the sleeve 26, the knob 30 engages the spring strip 10 for forcing the crystal in a direction away from the contact spring 24: by flexing the spring strip 10.

While I have herein shown and described the preferred embodiment of my invention, it is to be understood that numerous and various modifications may be made in the exact form, relationship and connection of parts without departing from the spirit and scope of the invention as claimed WhatI claimas new is:

1. In a crystal detector of the character described, a support,a resilient strip, a crystal element supported by said strip, a second support carried by the first named support and having-a contact spring flexibly connected thereto for being manually moved into contact with the surface of the crystalelement and over the surface of the latter, said resilient strip normally acting to move the crystal element carried thereby in one direction relative to the spring contact, and means engaged with the first named support for moving the resilient strip in an opposite direction relative to the spring contact, for eifecting a fine adjustment of the crystal element and spring. contact toward or away from each other and thereby regulate to a fine degree the: pressure with which the contact spring engages the surfaceof the crystal element. v

2, In a crystaldetector, a support, a. resilient strip carrying a crystal element, a contact spring flexibly connectedto the supcontact spring mounted on the base, and adjustable relative thereto for engagement with desired points on the surface of a or stal in said holder, and manually operable means for holding said spring strip under tension, and adjusting the tension thereof, to efiect a micrometric adjustment of contact pressure between the contact spring and 20 the crystal.

In testimony whereof I afiix my signature.

FREDERICK E. MANN. 

